Renesas M5M5256DFP-55LL#BM

Overview

M5M5256DFP-55LL#BM from Renesas is a 262,144-bit (32,768 × 8) CMOS static RAM in 28-pin SOP package, operating on single +5V supply with 55 ns access time, TTL-compatible I/O, and battery-backup capability down to +2.0 V. It serves as non-volatile data retention memory in embedded controllers, industrial PLCs, and legacy instrumentation requiring simple parallel interface and low standby current.

For engineers reviewing the M5M5256DFP-55LL#BM datasheet, M5M5256DFP-55LL#BM pinout, M5M5256DFP-55LL#BM application, or M5M5256DFP-55LL#BM equivalent, key selection criteria include 55 ns read cycle time, 0.05 µA typical standby current at Vcc = 5.5 V, /OE-controlled three-state outputs, /S and /W dual-control write enable, and direct compatibility with 5 V TTL bus systems without level translation.

Technical Context

This SRAM implements asynchronous parallel interface logic with chip-select (/S), write-enable (/W), and output-enable (/OE) control lines. Its operation mode-read, write, standby, or non-selection-is determined exclusively by the logic combination of these three inputs per the function table, with no internal clocks or refresh required.

It uses resistive-load NMOS memory cells with CMOS periphery for high density and low power, supporting data hold at +2.0 V during power failure. The device features common I/O pins (DQ1–DQ8), OR-tie capability via three-state outputs, and active-low control signaling fully compliant with standard TTL voltage thresholds (VIH = 2.4 V, VIL = 0.8 V).

Key Specifications

Pinout & Package

Package: 28-pin plastic SOP (Small Outline Package), 450 mil width (Outline 28P2W-C), surface-mountable with 1.27 mm pitch.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar static RAM applications.

Compared with IS61LV25616AL-10TLI and AS6C4008-55PCN, the M5M5256DFP-55LL#BM uniquely balances 55 ns speed, ultra-low 0.05 µA standby, and +2.0 V data retention in a 5 V TTL system-making it irreplaceable for legacy industrial designs requiring true zero-refresh, battery-backed operation.

Availability

M5M5256DFP-55LL#BM is available at Aetrix Electronics and suitable for industrial PLCs, legacy instrumentation, embedded controller bootloaders, and point-of-sale terminal buffers requiring stable component supply and long-lifecycle support.

Supply support for M5M5256DFP-55LL#BM includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Renesas Electronics Corporation is a Japanese semiconductor manufacturer specializing in microcontrollers, analog, power, and memory solutions for automotive, industrial, and infrastructure markets.

The M5M5256DFP-55LL#BM belongs to Renesas' legacy CMOS SRAM product line designed for reliability-critical, low-power, and pin-compatible replacements in mature industrial and instrumentation systems.

FAQ

What is the maximum access time specification for the M5M5256DFP-55LL#BM?

The M5M5256DFP-55LL#BM has a guaranteed maximum access time of 55 ns for read cycle time (t_CR), chip select access (t_a(S)), and output enable access (t_a(OE)). This value is tested under Vcc = 5 V ±10%, T_A = 25 °C, and CL = 50 pF, ensuring deterministic timing for integration with 12–15 MHz microcontrollers and FPGA interfaces without wait states.

Does the M5M5256DFP-55LL#BM support battery backup operation?

Yes, the M5M5256DFP-55LL#BM supports true battery backup: it retains stored data at supply voltages as low as +2.0 V, verified per its Power Down Characteristics table. This enables seamless operation during main power failure or controlled shutdown, making it ideal for applications like industrial loggers and medical devices requiring non-volatile state preservation without external EEPROM or FRAM.

What is the standby current of the M5M5256DFP-55LL#BM and under what conditions is it measured?

The M5M5256DFP-55LL#BM draws 0.05 µA typical standby current (Icc4) when /S = VIH and all other inputs are at valid logic levels, measured at Vcc = 5.5 V and T_A = 25 °C. This ultra-low value is confirmed in the DC Electrical Characteristics table and enables multi-year operation on coin-cell batteries in always-on monitoring systems.

Is the M5M5256DFP-55LL#BM pin-compatible with other variants in the M5M5256DFP,VP family?

Yes, the M5M5256DFP-55LL#BM shares identical pinout and package (28-pin SOP, Outline 28P2W-C) with all FP- and VP-suffix variants including -70LL, -70LLI, -55XL, and -70XL. Differences are limited to access time (55 ns vs. 70 ns) and temperature grade (0–70 °C vs. –40–85 °C), allowing drop-in replacement within the same speed/temperature bin without PCB changes.

How does the /OE pin function in the M5M5256DFP-55LL#BM during write operations?

In the M5M5256DFP-55LL#BM, the /OE pin operates independently of /W and /S: when /OE = high, outputs go high-impedance regardless of /W state, preventing data bus contention during writes. This allows safe simultaneous write to multiple memory devices sharing the same DQ bus, as confirmed in the Function Table and Timing Diagrams where /OE high forces DQ to high-Z even during active /W low pulses.